Gamestop Trade-In Values

Can somebody help me in finding the current trade-in value of these games at Gamestop/EBgames? Skyward Sword, Super Mario Galaxy, Super Mario Galaxy 2, Animal Crossing: City Folk, Mario Kart Wii, and Super Smash Bros. Brawl. I would love to sell these elsewhere but Gamestop Is the only place I can so I would be greatful for any help.

Can somebody help me in finding the current trade-in value of these games at Gamestop/EBgames? Skyward Sword, Super Mario Galaxy, Super Mario Galaxy 2, Animal Crossing: City Folk, Mario Kart Wii, and Super Smash Bros. Brawl. I would love to sell these elsewhere but Gamestop Is the only place I can so I would be greatful for any help.

It is kinda strange how the prices of used games move. Some new games go down in coupla of months, while some games stay pricey for years.
But in general, gamestop has pretty stiff prices for used nintendo games, compared to PS3 and xbox prices. which makes buying nintendo games a bit too costly for me. For example, old DS pokemons are still 40 euros per (second hand) game!!! What the heck...

I wonder if gamestop has something against nintendo. I mean if they dropped prices of used nintendo games to the same level as xbox games, they would be selling a lot more nintendo consoles too.
Also, they always have buy three, pay for two, sales for xbox games, but never for nintendo games.